Catalysts, to be used as exhaust gas purification for motor vehicles, have a structure in which a base member made of ceramics supports catalyst components. Because there are various kinds of catalyst components to be used for exhaust gas purification according to intended purposes and usage methods, it is difficult to select a target catalyst by its appearance. In order to avoid this problem, identification information regarding the catalyst to be used to purify exhaust gas, is often marked on an outer peripheral surface of the base member.
There has been proposed a marking method which applies an outer peripheral coating member containing titanium oxide onto an outer periphery of the base member to form a coated layer, and which irradiates a laser beam onto the coated layer (see Patent document 1). This marking method generates a black color in the area irradiated by the laser beam on the coated layer.